CN104047664B - Systems and methods for fluid pump outlet pressure adjustment - Google Patents

Abstract

A fluid pump pressure regulation system and method includes a valve having a valve body with a bore and a valve spool. The spool connects the first and second ports to the third port at different spool positions. The first port is in fluid communication with the fluid pump outlet to receive a first fluid pressure from the fluid pump. The second port is in fluid communication with the fluid container. The third port is in fluid communication with the input port of the fluid pump to provide a second fluid pressure to the fluid pump to control the first fluid pressure from the fluid pump. The linear actuator is adjacent the valve body such that the first spring and the second spring bias the valve spool in either the first or second direction.

Description

Systems and methods for fluid pump outlet pressure adjustment

technical field

The present invention relates to the adjustment of fluid pump outlet pressure; in particular, it relates to the adjustment of fluid pump outlet pressure according to engine speed.

Background technique

In the technical field related to fluid pumps such as engine oil pumps, it is well known that when the speed of the engine driving the pump is changed, in order to maintain the required pump outlet pressure, it is necessary to change the pump output (displacement) according to the pump outlet pressure. Adjusting the fluid pump outlet pressure increases engine efficiency by reducing the amount of oil pumped at higher engine speeds, resulting in energy savings.

Pressure-lubrication has been used in automotive internal combustion engines for many years. Typically, a single pressure relief valve is used to limit the maximum pressure developed by the oil pump. The pressure relief valve is usually set at a rather high value to ensure that the engine receives adequate lubrication under all operating conditions from idling to maximum speed-load operation. Unfortunately, this causes the energy consumption of the lubrication pump to be higher than would otherwise be ideal, since the engine requires only reduced oil volume and pressure under many operating conditions.

Other engine lubrication systems use electrically operated pressure control valves. A solenoid opens and closes the ball valve to control the pressure in the pilot chamber of the pressure valve.

It would be desirable to provide an engine lubrication system in which the engine is reliably protected by a pressure control valve combined with the ability of the engine to maintain oil pressure within a predetermined pressure range to promote improved fuel economy during all operating conditions.

Contents of the invention

In one embodiment, a fluid pump pressure regulating system includes a valve having a valve body with a bore and a spool slidably received in the bore. The valve body has a first port, a second port, and a third port in fluid communication with the bore. The spool selectively connects the first port and the second port to the third port at different positions of the spool within the bore. The first port is in fluid communication with the fluid pump outlet to receive a first fluid pressure at the first port, the first fluid pressure having a first pressure level. The second port is in fluid communication with a fluid container that provides a source of fluid to the fluid pump. The third port is in fluid communication with the control port of the fluid pump to provide a second fluid pressure at the third port, the second fluid pressure having a second pressure level that controls the first pressure level from the fluid pump.

A linear actuator is adjacent to the valve body and operatively coupled to the spool. A first spring biases the spool toward a second position relative to the valve body when a first pressure level at the first port is below a given threshold. When a first pressure level at the first port is above a given threshold, the spool is biased toward a first position wherein actuation and de-actuation of the linear actuator changes the given threshold level.

In another embodiment, a fluid pump pressure regulating system has a valve body with a hole having a first port, a second port, and a third port in communication with the hole. The first port is in fluid communication with the fluid pump outlet. The second port is in fluid communication with a fluid container that provides a source of fluid to the fluid pump. The third port is in fluid communication with the control port of the fluid pump, pressure applied to the control port controls the flow of fluid from the outlet of the fluid pump. The spool is slidably received within the bore and has a first position in which the first port is connected to the third port and a second position in which the second port is connected to the third port.

The actuator is adjacent to the valve body and is operably coupled to the spool. The first spring biases the spool to the second position when the pressure at the first port is below a given threshold level. When the pressure at the first port is greater than a given threshold, the spool is in a first position wherein actuation and deactivation of the linear actuator varies by the given threshold level.

In yet another embodiment, a fluid pump outlet pressure adjusting method includes the step of providing a hydraulic valve comprising a valve body with a hole, the valve body having a first port, a second port and a third port communicating with the hole. The first port is in fluid communication with a fluid pump outlet having a first pressure level. The first port will receive a first pressure level from the fluid pump. The second port is in fluid communication with a fluid container that provides a source of fluid to the fluid pump. A third port is in fluid communication with the control port of the fluid pump having a second pressure level, the third port providing the second pressure level to the fluid pump to control the first pressure level from the fluid pump. A spool is slidably received within the bore and has at least a first position and a second position. The first spring biases the spool towards the second position. A linear actuator is adjacent to the valve body and operably coupled to the spool. The steps include operating the linear actuator to apply a force to the spool, changing a pressure threshold at the first port that is required to move the spool and adjust a fluid pump outlet pressure.

Description of drawings

1 is a schematic diagram of an oil pump system for controlling the supply of lubricating oil to an internal combustion engine according to an embodiment of the present invention;

Figure 2 is a longitudinal sectional view through the pressure control valve used in the system of Figure 1, wherein the linear actuator is deactivated and the hydraulic valve is operated at high pressure;

Fig. 3 is a perspective view of an armature assembly in the pressure control valve shown in Fig. 2;

Figure 4 is a perspective view of another alternative armature assembly in a pressure control valve;

Figure 5 shows one end of an alternative squirrel cage that may be part of the bearing on the armature assembly shown in Figure 4;

Figure 6 is a perspective view of the squirrel cage shown in Figure 4;

Figure 7 is a plan view of the other end of the squirrel cage shown in Figure 4;

Figure 8 is a cross-sectional view taken along line 8-8 in Figure 4;

Figure 9 is a longitudinal sectional view through the pressure control valve of Figure 2, showing the pressure control valve with no applied current and no pressure applied to the first port;

Figure 10 is a longitudinal sectional view through the pressure control valve of Figure 2, showing the pressure control valve with no current applied and pressure applied to the first port;

Figure 11 is a longitudinal sectional view through the pressure control valve of Figure 2, showing the pressure control valve with current applied to the coil and pressure applied to the first port;

12 and 13 are graphs showing the effect of current applied to the coil on the pressure at the first port and the third port;

14-16 are longitudinal cross-sectional views through another alternative pressure control valve having inverse logic relative to the pressure control valve shown in FIG. 2;

Figure 17 is a longitudinal sectional view through another alternative pressure control valve and showing a fourth port valve; and

Figure 18 is a longitudinal sectional view through another alternative pressure control valve.

Detailed ways

Referring to FIG. 1 , there is shown a fluid pressure regulation system 20 for controlling the supply of lubricating oil 22 to an internal combustion engine 24 . The internal combustion engine 24 includes an oil pump 26 and an oil container 30 containing a supply of lubricating oil 22 . An oil distribution network 32 connects the internal combustion engine 24 with an oil pump 26 and an oil container 30 .

The fluid pressure regulating system 20 also includes a pressure control valve 36 . Pressure control valve 36 is in fluid communication with oil pump 26 , oil reservoir 30 , and oil distribution network 32 . A pressure control valve 36 is used to control the pressure of oil within the oil distribution network 32 and delivered to the internal combustion engine 24 .

Oil pump 26 is typically mechanically driven by rotation of an engine crankshaft (not shown), as is known in the art, although other pump arrangements are also known. However, oil pump 26 differs from conventional pumps in that its displacement (ie, output volume) can vary according to the level of pressure applied to control port 38 on oil pump 26 . Varying this pressure varies the flow rate that the oil pump 26 supplies from the oil reservoir 30 through the oil filter 42 to the cavity at the top of the engine 24 . From these pockets, the oil 22 flows by gravity through the engine 24 until returning to the oil container 30 .

It should be understood that the oil flow and oil pressure at the outlet 52 of the oil filter 42 may be directly related to the speed of the engine 24 if the displacement of the oil pump 26 is held constant. However, it is desirable to maintain the amount of oil 22 applied to the engine, and thus oil pressure, within predetermined ranges regardless of engine speed.

The pressure control valve 36 is used to vary the displacement of the oil pump 26 to maintain the oil flow within a predetermined range as the engine speed varies. To accommodate this, the pressure control valve 36 includes a hydraulic valve 44 attached to a linear actuator 46 . Each of them will be described in detail below.

Referring to FIGS. 1 and 2 , the hydraulic valve 44 has a valve bore 48 extending longitudinally therethrough, the hydraulic valve 44 having at least a first port 50 , a second port 54 and a third port 56 leading to the valve bore 48 . In the illustrated embodiment, the first port 50 receives pressurized oil 22 from the oil filter outlet 52 and the second port 54 allows the oil 22 to flow back to the oil container 30 . The third port 56 is connected to the control port 38 of the oil pump 26 . The third port 56 is located along the valve bore 48 between the first port 50 and the second port 54 . The first port 50 is typically connected to a source of pressurized fluid, such as an oil filter output 52 , while the second port 54 is typically connected to a return line 60 leading to the oil container 30 . An opening 64 at the end 66 of the valve bore 48 may be included to provide an alternative outlet port.

By changing the position of the spool 70 in the valve bore 48, the pressure from the oil pump 26 can be applied to the control port 38 to varying degrees, and alternatively, by connecting the second port 54 and the third port 56, the pressure in the oil container 30 can be Low pressure is applied to control port 38 of oil pump 26 . It will also be appreciated that the arrangement or placement of the ports may be varied, or called by different names, and still provide the same functionality.

The spool 70 is slidably received within the valve bore 48 . In some embodiments, the spool 70 has a first land 72 near the first end 74 and a second land 78 near the second end 80 such that the first concave portion 82 is interposed between the first land 72 and the second land. 78, thereby forming a groove 84 around the spool 70. A second reduced diameter recessed portion 86 extends between the first land 72 of the spool 70 and the first end 74 of the spool 70 . The first spring 90 biases the spool 70 away from the set screw 68 at the end 66 of the valve bore 48 . Specifically, the first spring 90 engages the spool 70 adjacent the first end 74 . The first spring 90 urges the spool 70 towards the linear actuator 46 . The second end 80 of the spool 70 is adjacent the end 92 of the valve body 94 that is secured to the linear actuator 46 .

The linear actuator 46 includes an electromagnetic coil 98 wound around a non-magnetic bobbin 100 having a central opening 104 . The linear actuator 46 also has two tubular pole pieces 106 and 108 . The upper pole piece 106 extends into one end of the bobbin central opening 104 , and the lower pole piece 108 extends into the other end of the central opening 104 adjacent to the valve body 94 . The two tubular pole pieces 106 and 108 are slightly spaced from each other within the bobbin 100 . Extending into the two tubular pole pieces 106 and 108 is an inverted cup-shaped solenoid 112 having an open end facing the valve body 94 and a closed end in the upper pole piece 106 . References herein to directional relationships and movements, such as up and down and up and down, refer to the relationship and movement of parts in the orientation shown in the drawings, which may not be the same as those parts when the valve is attached to the machine. orientation.

A ferromagnetic armature 114 is slidably received within the solenoid 112 and has a tubular push pin 116 secured in a central bore through the armature 114 . The push pin 116 may have a notch 120 at its upper end to allow fluid to enter when that end abuts the closed end 122 of the solenoid 112 . The push pin 116 and armature 114 move as a unit within the non-magnetic solenoid 112 in response to the electromagnetic field generated by the current flowing through the coil 98 . For example, electrical current may be applied to coil 98 by a computer-operated engine control unit.

The tubular configuration of push pin 116 allows oil 22 to flow between opposing sides of armature 114 during its motion. Push pin 116 protrudes from armature 114 toward valve body 94 and has a distal end 123 that engages sleeve 124 and is preferably secured to sleeve 124 . The sleeve 124 may serve as a guide for a second spring 126 extending between the sleeve 124 and the second end 80 of the spool 70 . Accordingly, the second spring 126 tends to bias the spool 70 away from the linear actuator 46 and toward the end opening 64 of the valve bore 48 . Armature 114, push pin 116 and sleeve 124 form armature assembly 128, however, two or all three of these components may be fabricated from a single block of material. Furthermore, the armature assembly 128 may have a different shape as long as it serves the same function, as will be described below.

Referring to FIGS. 2 and 3 , the bearing 130 may be mounted on the push pin 116 and may be part of the armature assembly 128 . Due to the magnetic flux at the end of the lower pole piece 108, an axial force is exerted on the armature 114, and the bearing 130 at this location prevents connection to the armature due to the axial force. In some embodiments, the bearing 130 may include a squirrel cage 132 fabricated from a non-magnetic material, preferably a resilient plastic. The cage 132 is a single piece having two spaced apart end rings 134 and 136 with five walls 138 extending between the end rings 134 and 136 equally spaced around the cage 132 . Each wall 138 has a generally Y-shaped cross-section, as shown in cross-section in FIG. 7, such that the cage 132 is wider at the outer curved surface than towards the center of the cage. Five longitudinal slots 140 are formed between adjacent ones of the five walls 138 . The outer surface of the wall 138 is concave, forming a longitudinal channel 142 extending the full length of the wall 138 . These channels 142 allow fluid to flow around the cage 132, which reduces resistance to sliding movement of the armature 114 that would otherwise occur due to restricted fluid flow.

As shown in FIGS. 2 and 3 , individual chrome balls 146 provide rollable elements within each groove 140 . The top of each generally Y-shaped wall 138 extends into each slot 140 thereby narrowing the opening of the slot in the curved outer surface of the cage 132 so that the ball 146 is captured and cannot exit the slot 140 freely. The plastic material of the squirrel cage 132 is resilient, allowing the adjacent walls 138 to spread out enough to allow the ball 146 to be inserted into the associated slot 140, and then return to its original position to retain the ball 146. Rings 134 and 136 at each end of cage 132 prevent ball 146 from moving out of slot 140 ends. The term "captured" as used herein means that the ball 146 is restrained by the wall 138 and the rings 134 and 136 of the squirrel cage 132 without the need for other components as in prior art armature assembly designs. As shown in FIG. 2 , each ball 146 protrudes from a corresponding slot 140 to contact the solenoid 112 and is capable of rolling within the corresponding slot 140 . Other forms of rollable elements, such as cylinders, may be used in place of balls 146 .

In an alternative embodiment as shown in FIGS. 4-8 , the squirrel cage 132 may include a detent 150 that includes five L-shaped fingers 152 that protrude outwardly from the second ring 136 such that the finger protrusions 154 protrudes into an annular groove 156 surrounding push pin 116 . Engagement of the finger protrusions 154 with the push pin annular groove 156 holds the squirrel cage 132 against the armature 114 . Alternatively, the squirrel cage 132 and push pin 116 may be manufactured as a single plastic part.

The components of the linear actuator 46 described thus far may be enclosed within an outer metal housing 160 that is crimped within a notch 162 surrounding the valve body 94 to secure the linear actuator 46 to the valve body 94 superior. In some embodiments, the solenoid coil 98 may comprise an overmolded plastic piece which may then be mounted within the housing 160 . In another alternative embodiment, plastic material may be injected into housing 160 to form an overmolded enclosure 164 that extends around solenoid coil 98 and protrudes through opening 166 in housing 160 to form a External electrical connector 170 for solenoid coil 98 . Metal end plate 172 closes the end of housing 160 remote from valve body 94 .

In one exemplary application, the pressure control valve 36 is adapted to be installed within the fluid pressure regulating system 20, wherein the oil 22 from the oil pump 26 is applied to the first port 50, wherein the return line 60 connected to the oil container 30 is connected to Second port 54. The third port 56 is connected to a device controlled by the pressure of the oil 22 (ie, the oil pump 26).

9 shows the de-energized state of the pressure control valve 36 when there is no current flowing through the solenoid 98, and when the pressure at the first port 50 is zero or substantially low, as would occur before starting the oil pump 26. of. At this point, the first spring 90 has a greater preload than the second spring 126 and the spool 170 is in the first position 168 . In this configuration, the oil pump 26 will have maximum displacement. In the first position 168 , the spool 70 is positioned such that the groove 84 around the spool 70 communicates with the first port 50 only. However, the second recessed portion 86 at the first end 74 of the spool adjacent to the first spring 90 provides a path 178 for the oil 22 to flow from the third port 56 to the second port 54 and to the oil reservoir 30 by Thus, any pressure is released at the third port 56 .

Referring to Figure 10, when the oil pump 26 is activated, the pressure at the first port 50 begins to increase. This pressure communicates with the second end 80 of the spool 70 through the pilot passage 180 , so that the same pressure exists in the pilot chamber 182 between the spool 70 and the sleeve 124 . When the pressure exceeds the first predetermined pressure threshold, the combined force of the pressure and the second spring 126 acting on the second end 80 of the spool 70 is greater than the reaction force of the first spring 90, thereby causing the spool 70 to move toward the first The downward movement of the second position 174 compresses the first spring 90 . When the pressure reaches a first predetermined pressure threshold, for example, 4.5 bar or more or less, the spool 70 moves to a position where the first zone 72 on the spool 70 closes the third port 56 and the second port 56. port 54, while the annular groove 84 communicates with the first port 50 and the third port 56, thereby providing a fluid path 184 therebetween. The fluid path 184 increases the pressure at the third port 56 which destrokes the oil pump 26 and prevents the oil pump from exceeding the first predetermined pressure threshold.

Thereafter, when the pressure at the inlet port 50 drops significantly, the first spring 90 forces the spool 70 upward into the position shown in FIG. 9 where the third port 56 can communicate with the second port 54 again.

Referring to FIG. 11 , when the solenoid coil 98 is energized with current, and the predetermined pressure threshold at the first port 50 is, for example, 4.5 bar, the electromagnetic field generated causes the armature 114 to move downward within the solenoid 112 , as shown in FIG. 10 . The position shown moves into the third position 176 in FIG. 11 . Because the armature 114 is coupled to the sleeve 124 via the push pin 116, the sleeve 124 also moves downward until it hits the upper end 92 of the valve body 94, which limits the amount of movement of the sleeve regardless of the force generated by the electromagnetic field. . This action initially compresses the second spring 126 whereby the force acting on the spool 70 is greater than the force against the first spring 90 . The unbalanced resultant force causes the spool 70 to move downwards to compress the first spring 90 . Once the sleeve 124 rests on the upper end 92 of the valve body 94, the two springs 90 and 126 again achieve force balance which positions the spool 70 in a further downward position than before the solenoid coil 98 was energized. In this third position 176 , the first port 50 is connected to the third port 56 by a path 188 around the spool annular groove 84 .

The downward displacement of the spool 70 caused by energizing the linear actuator 46 compresses the first spring 90 and the second spring 126 more than when the linear actuator is de-energized. The compression of the first spring 90 changes, inter alia, the amount of pressure required to move the spool 70 at the first port 50 into the third position 176 where the path 188 is formed between the first port 50 and the third port 56. between. This fluid path 188 in turn increases the pressure at the third port 56 which destrokes the oil pump 26 and reduces the pressure from the oil pump 26 to a level less than the first predetermined pressure threshold.

The amount of pressure that needs to be applied to the first port 50 (the second predetermined pressure) for this action to occur is less than the first predetermined pressure threshold required to form the path 184 (see FIG. 10 ) when the linear actuator 46 is de-energized. The second predetermined pressure may be determined by the stroke of the sleeve 124 and the spring rate or spring force of the second spring 126, but is not affected by the electromagnetic force, which eliminates the need for precise control of the force. Thus, by selectively energizing and de-energizing the linear actuator 46, the pressure at the first port 50 required to open communication between the first port 50 and the third port 56 can be set at two different under predetermined pressure. Selecting a particular pressure changes the pressure response characteristics of the pressure control valve 36 and likewise changes the operation of the oil pump 26 connected to the third port 56 .

This response is shown in the graphs of FIGS. 12 and 13 . Let the pressure of the first port 50 be approximately 4.5 bar, and the pressure of the third port 56 be approximately 0.4 bar, when the current 190 flowing to the coil 98 increases to approximately 0.4 amperes, the spool 70 starts to move, causing the pressure at the first port 50 to The pressure at the third port 56 rises as the pressure drops. As the current 190 continues to increase, approximately 0.9 amps, the pressure at the first port 50 decreases, plateaus to approximately 1.0 bar, and the pressure at the third port 56 increases to approximately 0.8 bar and plateaus. Figure 13 shows a predetermined pressure range 192 of about 1.0 bar to about 4.5 bar. It should be appreciated that the predetermined pressure range 192 may vary according to the requirements of a particular application.

Another alternative configuration for the pressure control valve 236 is shown in FIGS. 14-16 . Pressure control valve 236 is similar to pressure control valve 36 , except that pressure control valve 236 includes a spool 270 configured to provide the reverse logic to pressure control valve 36 . For example, FIG. 14 shows the de-energized state of the pressure control valve 236 when no current is flowing through the solenoid 98 and when the pressure at the first port 50 is zero or substantially low. At this point, the first spring 90 has a greater preload than the second spring 126 and the spool 70 is in the first position 268 . In this configuration, the oil pump 26 will have maximum displacement. In the first position 268, the spool 270 is positioned such that the groove 84 around the spool 270 communicates with the first port 50 and the third port 56 provides a path 278 for the oil 22 to flow out of the third port 56 and towards the control port 38. The spool 270 will stay in this position until the pressure at the first port 50 reaches a predetermined pressure, eg 4.5 bar.

Referring to FIG. 15 , when the pressure at the first port 50 rises, the pressure overcomes the preload of the second spring 126 through the pilot passage 180 to push the spool 270 down. When the pressure at the first port 50 reaches a predetermined pressure, the spool 270 reaches force balance and reaches the zero position 274 .

Referring to FIG. 16 , thereafter, when solenoid coil 98 is energized with current applied, the generated electromagnetic field causes armature 114 to move down within solenoid 112 from the position shown in FIG. 15 to position 276 in FIG. 16 . Because the armature 114 is coupled to the sleeve 124 through the push pin 116, the sleeve 124 also moves down until the sleeve hits the upper end 92 of the valve body 94, which limits the amount of movement of the sleeve regardless of the force generated by the electromagnetic field. . This action initially compresses the second spring 126 , whereby the force acting on the spool 270 is greater than the force against the first spring 90 . The unbalanced resultant force causes the spool 270 to move downward and compress the first spring 90 . Once the sleeve 124 rests on the upper end 92 of the valve body 94, the two springs 90 and 126 again achieve force balance which positions the spool 270 in a further downward position than before the solenoid coil 98 was energized. In this third position 276 , the second port 54 is connected to the third port 56 by a path 288 around the spool annular groove 84 .

Referring to Figure 17, another alternative configuration for the pressure control valve 336 is shown. Pressure control valve 336 is similar to pressure control valves 36 and 236 , except that pressure control valve 336 includes a fourth port 358 . With the pressure control valves 36 and 236 of the three port type, the third port 56 pressure can never exceed the first port 50 pressure which is the oil filter outlet pressure 52 . For the four port pressure control valve 336, the pilot signal at the fourth port 358 is the oil filter outlet pressure 52, the first port 50 receives the pump discharge pressure 28, which due to the pressure drop across the oil filter 42, the pump discharge pressure 28 Greater than oil filter outlet pressure 52. In this case, the pressure of the stop stroke may be equal to the pump discharge pressure 28 and exceed the oil filter outlet pressure 52 . This allows the oil pump 26 to use a stiffer spring (not shown), which can provide a more stable oil pump.

Referring to Figure 18, another alternative configuration for the pressure control valve 436 is shown. Pressure control valve 436 is similar to pressure control valves 36 , 236 , and 336 , except that pressure control valve 436 includes pin 440 positioned between spring 126 and spool 470 . The pin 440 has a reduced diameter 442 and can extend from the pilot chamber 182 to the valve bore 48 . The reduced diameter pin 440 allows the pressure control valve 436 to control a greater pressure range without requiring greater linear actuator 46 force. The spool 470 and the valve bore 48 may each have a larger diameter, which may increase the fluid flow area. It should be appreciated that pin 440 and spool 470 may be formed from a single piece or from multiple pieces of material.

Referring again to FIG. 1 , when the engine 24 speed increases and the oil filter outlet pressure 52 also increases, the increased pressure is applied to the pilot chamber 180 and, through the first port 50 , to the pilot valve at the top of the spool 70 . Chamber 182 (see also FIG. 2 ). Even though the armature 114 remains in a fixed position, because the current 190 to the coil 98 is unchanged, the increased pressure in the pilot chamber 182 pushes down on the spool 70 and opens the path 184 between the ports 50 and 56 (see FIG. 10). This increased pressure is communicated through path 184 to the control port 38 of the oil pump 26, thereby reducing the displacement of the oil pump 26 and the outlet flow and pressure at the outlet 52 of the oil filter, i.e. the higher the control pressure the smaller the displacement .

As the speed of the engine 24 decreases, the opposite action occurs, causing the pressure in the pilot chamber 182 to decrease as well. Due to the low pressure in the pilot chamber 182, the first spring 90 pushes up the spool 70, opening the path 178 between the third port 56 and the second port 54 (see FIG. 9). This path 178 reduces the pressure at the control port 38 of the oil pump 26 thereby increasing the displacement of the oil pump 26 and the pressure at the oil filter outlet 52 . In this way, the outlet pressure and flow of oil 22 to the engine 24 is maintained within the predetermined pressure range 192 as the engine speed varies.

The pressure level to which the oil filter outlet pressure 52 is controlled can be adjusted by the level of current applied to the coil 98 within the linear actuator 46 . Adjusting the current 190 changes the magnetic field generated by the coil 98 and thereby changes the position of the armature 114 within the linear actuator 46 . The variable position of the armature 114 can compress or relax the first spring 90 and the second spring 126 , thereby applying different spring forces to the first end 74 and the second end 92 of the spool 70 , respectively. These forces define the pressure values required to move the spool 70 within the pilot passage 180 and the pilot chamber 182 to pilot. As a result, varying the current 190 applied to the linear actuator 46 can affect the spool 70 to open and close the paths between the third port 56 and the first port 50 (paths 184 and 188) and the third port 56 and the return port. The pressure level at the path between 54 (path 178). Changing this pressure level can change the pressure within the predetermined pressure threshold range 192 to which the oil filter outlet 52 pressure is to be controlled.

The above description mainly relates to preferred embodiments of the invention. While some attention has been given to various alternatives within the scope of the invention, it is expected that those skilled in the art will also recognize other additional alternatives which are now apparent from the disclosure of the embodiments of the invention. Accordingly, the scope of the invention should be determined by the appended claims and not limited by the foregoing disclosure.

Claims (22)

1. a kind of fluid pump pressure adjusts system, including：

Valve, the valve have valve body with holes and the spool that is slidably received in the hole, the valve body have with it is described First port, second port and the 3rd port that hole fluidly connects, the hole include adjusting screw, and the valve body is included in institute State in valve body and outwards arranged from the hole to provide the preceding pathway between the first port and the second end of the spool, The first port and the second port are selectively connected to by the diverse location of the spool in the hole, the spool 3rd port；

The first port, the first port are fluidly connected with Fluid pump outlet to receive first at the first port Fluid pressure, the first fluid pressure have first pressure level；

The second port, the second port are fluidly connected with fluid container, and the fluid container puies forward the fluid pump For fluid source；

3rd port, the 3rd port are fluidly connected with the control port of the fluid pump to provide the 3rd end Second fluid pressure at mouthful, the second fluid pressure have second pressure level, and the horizontal control of the second pressure comes from The first pressure level of the fluid pump is to the value between the first predetermined pressure and the second predetermined pressure；

Linear actuator, the linear actuators are adjacent to valve body and are operationally coupled to the spool；

First spring, first spring are connected to the adjusting screw and and opposite with the second end with the spool When first end coordinates the level less than given threshold value horizontal with the first pressure at the first port, first spring The spool is biased relative to the valve body towards the second place；And second spring, the second spring is by the spool Biased towards first position,

Wherein, when the first pressure at the first port is horizontal horizontal higher than the given threshold value, the spool quilt Biased towards the first position, and wherein, the actuating and stopping actuating of the linear actuators change the given threshold value Level, so as to being proportionally controlled the first pressure level described with being applied to the size of current of the linear actuators Between first predetermined pressure and second predetermined pressure.

2. the system as claimed in claim 1, it is characterised in that

Second spring is further included, the second spring extends between the linear actuators and the spool, and described in coupling Linear actuators and the spool.

3. the system as claimed in claim 1, it is characterised in that

When the second pressure is horizontal to be increased, the first pressure is horizontal to be reduced.

4. the system as claimed in claim 1, it is characterised in that

When the second pressure is horizontal to be reduced, the first pressure is horizontal to be reduced.

5. the system as claimed in claim 1, it is characterised in that

The first pressure level is the first variable level of fluid pressure, and the second pressure level is the second variable stream Body stress level；And

Wherein, the second convertible fluids stress level at the control port of the fluid pump controls fluid pump, with Described first variable level of fluid pressure is maintained in the range of predetermined fluid pressure.

6. the system as claimed in claim 1, it is characterised in that

With engine fluid connected from the fluid pump and the first pressure of fluid container level.

7. the system as claimed in claim 1, it is characterised in that

The fluid pump is the variable fluid pump of discharge capacity.

8. the system as claimed in claim 1, it is characterised in that

The spool is to the path between the mobile opening first port of the first position and the 3rd port, and institute Spool is stated to another path between the mobile opening second port of the second place and the 3rd port.

9. the system as claimed in claim 1, it is characterised in that

When the linear actuators is powered, the given threshold value is horizontal to be reduced.

10. system as claimed in claim 9, it is characterised in that

The given threshold value level is electrically controlled.

11. a kind of fluid pump pressure adjusts system, including：

Valve body, the valve body are with holes and with first port, second port and the 3rd port fluidly connected with the hole, institute Stating valve body includes being arranged in the valve body from the outwardly extending preceding pathway in the hole, the first port and Fluid pump outlet Fluidly connect, the second port is fluidly connected with fluid container, and the fluid container provides fluid to the fluid pump Source, the 3rd port are fluidly connected with the control port of the fluid pump, wherein, it is applied to the pressure of the control port The fluid flow from the Fluid pump outlet is controlled, the hole includes adjusting screw；

Spool, the spool are slidably received in the hole, and have first position and the second place, described first Position, the first port are connected to the 3rd port, and in the second place, the second port is connected to the described 3rd Port, the preceding pathway provide the fluid communication between the first port and the second end of the spool；

Actuator, the actuator are adjacent to the valve body and are operationally coupled to the spool, and the actuator includes electricity Pivot, the armature is with being coupled to the current in proportion of the spool and the coil with being applied to the armature in the first armature position Moved between the second armature position；

First spring, first spring are connected to the adjusting screw and and opposite with the second end with the spool When first end cooperation is less than given threshold value with the pressure at the first port, the spool is biased into by first spring Enter the second place；And

Second spring, the second spring bias the spool towards first position,

Wherein, when the pressure at the first port is horizontal higher than the given threshold value, the spool is in described first In putting, and wherein, actuating of the armature between first armature position and second armature position is with being applied to institute Change the given threshold level with stating the current in proportion of the coil of armature.

12. system as claimed in claim 11, it is characterised in that

Second spring is further included, the second spring extends between the linear actuators and the spool, and described in coupling Linear actuators and the spool.

13. system as claimed in claim 11, it is characterised in that

The actuator includes solenoid coil component and armature, and the solenoid coil component, which has, is formed in the solenoid Coil hole in coil block, the armature are slidably received in the coil hole, and be operationally coupled and by power It is applied to the spool.

14. system as claimed in claim 12, it is characterised in that

The actuator changes the power being applied to by the second spring on the spool, to change needed for the mobile spool The first port at the given threshold level.

15. system as claimed in claim 11, it is characterised in that

Fluid pressure from the Fluid pump outlet and the fluid container, with engine fluid connects；And

When the engine speed changes, the given threshold value level becomes between first pressure level and second pressure level Change, to control the fluid pump, the Fluid pressure from the Fluid pump outlet is maintained to predetermined Fluid pressure model In enclosing.

16. a kind of Fluid pump outlet pressure method of adjustment, the described method includes：

Hydraulic valve is provided, the hydraulic valve includes：

Valve body, the valve body are with holes and with first port, second port and the 3rd port connected with the hole, the valve body It is included in the preceding pathway outwards arranged from the hole in the valve body, the first port and the stream with first pressure level Body pump discharge fluidly connects, and it is horizontal that the first port will receive the first pressure from the fluid pump, and described second Port is fluidly connected with fluid container, and the fluid container provides the fluid pump fluid source, the 3rd port and tool The control port for having the fluid pump of second pressure level fluidly connects, and the 3rd port provides the to the fluid pump Two stress levels, to control the first pressure level from the fluid pump to the first predetermined pressure and the second predetermined pressure Between value, the hole includes adjusting screw；

Spool, the spool is slidably received in the hole and has at least first position and the second place, before described Pathway provides the fluid communication between the first port and the second end of the spool；

First spring, first spring are connected to the adjusting screw and and opposite with the second end with the spool First end coordinates so that the spool to be biased towards the second place；

Second spring, the second spring bias the spool towards the first position,

Linear actuators, the linear actuators are adjacent to the valve body and are operationally coupled to the spool；And

The linear actuators is operated, the current in proportion with being applied to the linear actuators is exerted a force to described On spool, wherein the power that is applied on the spool changes the pressure threshold at the first port, the pressure threshold be with With being applied to the current in proportion of the linear actuators the mobile spool and thus first predetermined pressure with it is described Adjusted between second predetermined pressure needed for the Fluid pump outlet pressure.

17. the method described in claim 16, it is characterised in that

The first position provides the path between the first port and the 3rd port.

18. the method described in claim 16, it is characterised in that

Run the linear actuators and the power is applied on the spool including running the linear actuators, by institute Pressure threshold is stated one of to change to multiple stress levels.

19. the method described in claim 16, it is characterised in that

Run the linear actuators and include running the linear actuators and the power is applied on the spool, with the Change the pressure threshold between one pressure threshold level and second pressure threshold level.

20. the method described in claim 16, it is characterised in that

The second pressure is horizontal horizontal less than the first pressure.

21. the method described in claim 16, it is characterised in that

Further include the speed for changing the engine fluidly connected with the fluid pump；And

The fluid pump output pressure is maintained within predetermined pressure output area.

22. method as claimed in claim 21, it is characterised in that

Further include with electric current to control the predetermined pressure output scope.